Photoregulated supramolecular hydrogels driven by polyradical interactions

Organic radical as a powerful tool has been extensively applied in synthetic chemistry. However, harness-ing radical-mediated noncovalent interactions to fabricate soft materials remains elusive. Here we report a new category of supramolecular hydrogel system held by multiple radical-radical (polyradical) inter-actions, and its photosensitive cross-linking structure. A simple polyacrylamide with triarylamine (TAA) pendants is designed as the precursor. The TAA units in polymer can be converted into active TAA ' + rad-ical cations with light and further associate each other via TAA' + -TAA' + stacking interactions to form stable supramolecular network. Temporal control of the light irradiation dictates the degree of radical stacks, thus regulating the mechanical performance of the resulting hydrogel materials on-demand. More-over, the reversible collapse of this hydrogels can be promoted by adding radical scavenger or exerting reduction voltage.(c) 2023 Published by Elsevier B.V. on behalf of Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.

Automated summary

A new category of supramolecular hydrogel system held by multiple radical-radical interactions is reported, with photosensitive cross-linking structure. The mechanical performance of the resulting hydrogel materials can be regulated by temporal control of light irradiation, and the reversible collapse of the hydrogels can be promoted by adding radical scavenger or exerting reduction voltage.